Ejection apparatus



Jan' 1962 W. E. EJECTION .APPARATUS Filed 12,

30 I nl x 4,6 58 KSO m 6 60 26u. nl W39 5s 28 il. l i A I 4 VDI Fig, 5

3,6 i 3s *L i r- Fly. 4

. INVENTOR.

WALTER E HoLTZ Fig, 2

ATTORNEYS tet hline Ell Patented Jan. Z3, i962 3,lll7,835 EJECTHNAPPARATUS Walt-er E. Holtz, Pomona, Calif., assigner to the UnitedStates of America as represented by the Secretary of the Navy Filed Ang.12, 1958, Ser. No. 754,695 l Claim. (Cl. 102-49) (Granted under rlittle35, US. Code (1952), see. 266) The invention described herein may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes without the payment of any royaltiesthereon or therefor.

The present invention relates to apparatus operating subsequent to thesurface launching of a missile for cnsurinf the complete ejection ofcomponents which, if retained during flight, would have an adverseeffect on missile performance.

Data obtained during the testing and evaluation of surface-launchedguided missiles indicates that a considerable improvement in speed and/or range could in many cases be achieved by reducing the drag whichresults from failure of the missile to rid itself of certainoutwardly-projecting structural components utilized only during thelaunching operation.

One presently-employed launching technique incorporates Ya plurality ofguide rails upon which a boosteraided surface-to-surface missile ispositioned for tiring. To provide for slidable engagement between themissile and this supporting structure, a number of rail-engagingadaptors, commonly referred to as slippers, are respectively connectedto the missile body by means of an equal number of detachableoutwardly-extending supports. These slippers and their associatedsupports remain with the missile until after the latter leaves thelaunching pad.

At the time of booster burnout, the expended booster chambers areejected from the missile. In many designs, this booster chamber ejectioncauses a valve to open and admit a iluid under pressure to cylindersrespectively associated with the slipper supports. This compressed fluidexerts a force against a piston fo-rming an integral part of eachsupport, thereby resulting in an ejection of the supports from themissile.

Experience has shown the percentage of failures of this slipper-ejectionapparatus to be higher than warranted by operational conditions.Intensive study of the cause of the failures points clearly to a lowvelocity of ejection as the prirne contributing factor.

rFhe principal objective of the present invention, therefore, is toprovide means for increasing the ejection velocity of ya missiie slippersupport over that obtained by methods heretofore employed.

Another object of the present invention is to provide a structurethrough which the pressure behind a missile slipper may build up to apoint Where high-speed ejection of such support may take place, thelatter being securely retained in position throughout the period ofpressure build-up.

A further object of the invention is to provide means for raising thepressure level at which slipper support ejection actually begins, andfor maintaining at least a portion of this ejection pressure until suchtime as complete ejection of the slipper support has been effected.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. l is a partly schematic view of a missile positioned on a launchingplatform by a plurality of slippers and supports of a type with whichthe present invention may be utilized;

FIG. 2 is a partly sectional View of a single missile slipper supportincorporating a preferred embodiment of the present invention, alsoshowing that portion of the missile body with which such support isassociated:

FlG. 3 is a sectional view of FIG. 2 taken along the line lll-lll; and

FIG. 4 is a view of a portion of FIG. 2 showing a modified form of amechanical restraining device for the slipper support.

in FIG. l of the drawings is illustrated a missile 10 (which may be ofthe surface-to-surface type) supported in tiring position upon a more orless conventional launching platform or pad generally identified by thereference number l2. The launching platform l2 includes a pair offorward parallel guide rails 14 as well as a pair of rearward parallelguide rails 16, only one rail of each pair being visible in the drawing.lt will be understood, however, that each such pair of guide rails 14,ld, as well as the general missile assembly to be hereinafter set forth,is of symmetrical design, and hence it is believed that a detaileddescription of the components illustrated in FIG. l will provide acomplete understanding of the environment in which applicants inventionis to be utilized.

During the initial portion of its movement the missile lt) rides alongthe rails f4 and i6, actual contact being through a pair of forwardslippers7 i8 and a pair of rearward slippers Ztl, all of which membersare of course congured to engage the surface of the guide rails alongwhich they travel as the missile lll is caused to move followingignition of its booster rockets (not shown). Two pairs of arm-likesupports 22 and 24 respectively connect the two pairs of slippers l andZtl to the body of missile lll.

lt might be mentioned that the body of missile lll is cradled betweenthe two guide rails of each pair, and that the slope of the forward pairis somewhat greater than that of the rearward rails in order to impartaninduced pitch to the missile as it leaves the launching area. Althoughnot shown, a plurality of booster rockets are customarily attached tothe missile lll to aid it in reaching a speed where its jet propulsionunit becomes effective. Such an expedient is standard practice, however,and is referred to only because the present invention may in oneembodiment employ an ejection of the expended chambers of these boosterrockets to initiate a series of events which leads to fa similarejection of the slipper support members after they, like the boosterrockets, have served their purpose successfully launching the missile.

FlG. 2 of the drawings illustrates a preferred construction for theslipper supports 22, 24 of FIG. l, all of these supports being identicalin design and hence capable of being covered by the single descriptionwhich follows. The principal component of each slipper support is anS-shaped arm 26 which is of essentially circular crosssection throughoutits length, except for a portion 26a that is of generally square outlinein that region where the arm enters a matching opening 28 formed in atting 30 which constitutes part of the missile body. The surfacecovering or skin 32 of the missile is apertured in front of this opening2S to admit the arm 26, as illustrated. The reason for making the armportion 26a (as well as the opening 23) of noncircular cross-section isto preclude a rotation of the arm within the tting 30. Such a relativemovement between these members would prevent a correct positioning ofthe missile l0 on the platform l2 and hence reduce the chances for asuccessful launching operation.

Both the slipper support arm portion 26a and the opening 2S in thefitting 3@ are symmetrical about an axis 34 which lies in a horizontalplane. The opposite end of arm 26, which carries one of the slippers 18,20 (positioned within the boundaries indicated by the broken line 36)has an axis 38 which also lies in a horizontal plane. The slippercarried by this arm portion is thus maintained in position to slidablyengage one of the guide rails 14, 16 of the launching platform 12.

The slipper arm portion 26a (which as stated is of square outline) has acylindrical extension 40 receivable in a corresponding opening 42 formedin fitting 30, the openings 23 and 42 having the common axis 34 asillustrated. A shoulder 44 between arm portions 26a and 40 abuts asurface discontinuity 46 between openings 28 and 42 to limit the inwardprogress of the slipper support and thereby create a chamber 43 betweenthe end of the cylindrical extension 40 and a Vface plate 50 which issecured to the rear surface 52 of the slipper fitting 30. A conduit 54leads to an opening 56 in the face plate 50, this opening beingconcentric with opening 42. Fluid (such as gas) is admitted throughopening 56 to chamber 48 from a pressurized source in the missile (notshown). When the pressure of this fluid in chamber 48 reaches a pointwhere it is able to overcome the resistance offered by the frictionalengagement between the surface of the slipper support arm portions 26aand 40, on one hand, and the inner surface of the openings 28 and 42 inthe tting 30, on the other, the slipper support is ejected from themissile. The extension 40 thus acts as a piston, and a compression ringS8 receivable in an annular recess 60 in the surface of the pistonprovides a substantially fluid-tight seal between such member and theWall of opening 42.

Even though the pressure of the fluid in chamber 48 is sufcient toovercome initial frictional resistance, the slipper support arm 26 doesnot always attain suicient outward momentum to completely clear thefitting 30. It should be noted that support arm portion 26a andextension 40 for structural reasons are of substantial length, and thatthe volume of chamber 48 increases accordingly as the arm is beingejected. This is due in part to losses in the conduit 54 which lengthenthe period required for chamber pressure build-up. The result of such arelatively slow pressure increase is that the slipper support is movedoutwardly in gradual fashion rather than abruptly. In fact, if thepressure mounts at less than a critical rate, the slipper support willbe moved to a position where the piston 40 may clear the cylinderopening 42, but portion 26a will still be in frictional engagement withthe walls of opening 2S. At this point, a sequence valve (not shown)will close to cut E the supply of fluid, and no further pressure will beimparted to the support arm 26. Hence, the latter will not clear themissile if its velocity is insuflicient at the time this valve closureoccurs.

An additional factor bearing on the above is that lateral accelerationof the missile during the boost phase of its ight may cause the slippersupports 22, 24 to move outwardly. If a particular support moves out farenough to clear the sequence-valve contact button (not shown), thatvalve will close and thus isolate the cylinder from the pressure source.If the support moves some distance outward, but not far enough to clearthe sequence valve, ejection failure may still result because theshorter-than-normal engagement of the piston with the cylinder mayresult in lower ejection velocity.

To overcome the above drawbacks, the present invention provides meansfor restraining the movement of the slipper support, such restrainingmeans comprising in the preferred embodiment of FIGS. 2 and 3 a shearpin 62 receivable in two linearly-aligned openings 64 and 66respectively formed in the slipper support portion 26a and in the tting30. The aligned openings 64 and 66 are disposed at an angle to theprincipal axis 34 of the assembly, as best shown in FIG. 2. To preventan inadvertent withdrawal or loss of this shear pin, a safety wire 68encircles the support arm 26 and passes through a loop 70 formed on theouter end of the shear pin.

A restraining device of the above type yields the following advantages:

(1) It prevents motion of the slipper support 26 until enough force hasbeen developed on the piston 40 to cause release of the restrainingdevice.

(2) It definitely prevents outboard motion of the slipper support 26 asa result of lateral acceleration of the missile 10.

Although the provision of such a mechanical restraining device doespermit a slightly larger amount of compressed fluid to accumulate in thedevice chamber 48 prior to ejection of the slipper support, optimumejection velocity can be attained only if a considerably larger quantityof fluid is made available for expansion. Such a marked increase in thevolume of fluid stored would correspondingly increase the potentialenergy available to impart a higher ejection velocity to the slippersupport. However, this larger volume of stored lluid should be locatedin close proximity to the cylinder 42 so as to minimize line losses,and, in an optimum design, should communicate directly therewith. Thereason for this requirement is that the elapsed time between theinitiation of piston movement and the ejection of the slipper supportfrom the missile body is too short to permit any appreciable amount offluid to flow through conduit 54 and thus act to sustain cylinderpressure. Consequently, maximum ejection velocity must be developedearly in the ejection cycle.

In order to make a large quantity of compressed Huid available directlyat the point of utilization, a so-called accumulator,n or fluidreservoir, is formed directly in the slipper support arm. Thisaccumulator consists of an elongated cylindrical cavity 72 in the piston40 which is preferably drilled so as to be coaxial not only with theouter surface of the piston but also with the opening 56 in the faceplate 50. This cavity or chamber 72 has a volume considerably greaterthan that of chamber 48. In fact, optimum results are obtained when thefluid storage ratio (by weight) is approximately 6 to 1. The weight ofthis uid, in turn, is a function of the pressure required to cause therestraining device (such as shear pin 62) to release.

Although it might be expected that the presence of cavity 72 wouldappreciably reduce the over-all strength of the slipper support,experiments do not confirm this view. When an opening 6 inches long andof 29/32 inch diameter was drilled in a piston of 1.75 inch diameter,the margin of safety dropped only from 1.16 to 1.05. However, averageejection velocity of the slipper support increased from 10.6 feet persecond to 21.7 feet per second, or a ratio of approximately 2.05 to 1.The size and/ or composition of the shear pin 62 is not critical, andboth 1716 inch diameter brazing rod and Ms inch diameter music wire havebeen employed with satisfactory results.

In FIG. 4 is shown a form of mechanical restraining device which may besubstituted for the shear pin 62 of FIGS. 2 and 3. This assemblyincludes a detent 74, a spring 76 urging the detent 74 into a depression78 formed in the surface of the support arm portion 26a, and a set screw80 accessible from the exterior of fitting 30. By rotation of screw 80,the tension of spring 76, and hence the amount of fluid pressurerequired to eject the slipper support, may be manually determined. Otherarrangements may also be employed to prevent the slipper supports frommoving in an outboard direction until a certain fluid ejection pressurehas been attained. These may include, for example, a wire or cableplaced under tension by the pressure of accumulated fluid, or a linkassembly which will fail in tension when a predetermined loadingpressure has been reached.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specically described.

I claim:

Slipper ejection apparatus for a missile comprising a source of fluidunder pressure, a slipper support receivable in part Within acylindrical recess in the body of said missile, that portion of saidslipper support receivable within the said cylindrical recess being inthe form of a piston having an elongated cavity coaxially formedtherein, means for admitting fluid under pressure from said source tosaid recess and thence to the cavity formed in said piston to till thelatter, means for restraining movement of said piston in said recessuntil after the uid received by said cavity from said source has reacheda predetermined pressure, the fluid lling said cavity becoming eectivethrough expansion upon removal of the restraint imposed by saidlast-mentioned means to produce a sustained force on said piston duringthe initial phase of its movement and thereby ensure the completeejection thereof from the body of said missile.

References Cited in the file of this patent UNITED STATES PATENTS

